Flashtube socket assembly



July 21, 1964 w. A. WARD 3,141,983

FLASHTUBE SOCKET ASSEMBLY Filed NOV. 2. 1961 5 Sheets-Sheet 1 FIG. IA

INVENTOR.

WILLIAM A. WARD "ML/W24 I ATTORNEY July 211 .1964 ,A. WARD 331415983 JFLASH'RUBE socx-aw ASSEMBLY Filed Nov. 2. 1961 5 Sheets-Sheet :2

FIG. 5

FIG.2

INVENTOR. WILLIAM A. WARD ZZ/KM ATTORNEY July 21, 1964 w. A. WARD 3 FLASHTUBE SOCKET ASSEMBLY Filed NOV. 2. 1961 5 Sheets-Sheet 5 POWER SUPPLY CUIT CONTROL CIR FIG? 3 INVENTOR.

WILLIAM A. WARD ATTORNEY July 21, 1964 w. A. WARD 3,141,983

FLASHTUBE SOCKET ASSEMBLY Filed Nov. 2. 1961 5 Sheets-Sheet s FIG.9

I I I I I I I a A FIG. 8

INVENTOR. WILLIAM A. WARD BY y? ATTORNEY United States Patent Office 3,141,983 Patented July 21, 1964 3,141,983 FLASHTUBE SOCKET ASSEMBLY William A. Ward, Norwooil, Mass, assignor to Edgerton,

Germeshausen & Grier, Inc., Boston, Mass, :1 corporation of Massachusetts Filed Nov. 2, 1961, Ser. No. 149,739 3 Claims. (Cl. 3tl7157) The present invention relates to gaseous-discharge fiashtubes having a plurality of outwardly extending contact prongs such as disclosed in patent application Serial No. 78,587, filed on December 28, 1960, by Kenneth J. Germeshausen and John L. Turner, and more particularly to a unique socket assembly into which such flashtubes may be inserted.

The construction of the flashtube disclosed in said application has proved to be superior to those previously known; however, the additional space needed for the circuit elements required to operate said flashtube has proven to be a limitation on the use of the flashtube. Many equipments utilizing this fiashtube are employed in restricted spaces, and it is one of the objects of the present invention to provide a llashtube and circuit assembly which can be constructed in a small volume.

It has also proven costly and difiicult to connect each of the elements required in a circuit to operate a flashtube of this type, particularly because of the restricted space in which the flashtube assembly is used, because of the relatively high potentials involved and because of associated radiation which is minimized with this compact construction. This difficulty occurs particularly in equipment used in aircraft where explosive atmospheres exist from time to time and where spurious radiation must be minimized. It is therefore an object of the present invention to provide a combination socket assembly which includes a number of circuit elements for operating the fiashtube.

These and further objects of the present invention will be more fully appreciated upon a further consideration of this disclosure, particularly when viewed in the light of the accompanying drawings, in which:

FIGURE 1 is an enlarged top View of the socket assembly of the present invention;

FIGURE 1A is an enlarged bottom view of a flashtube of said application illustrating the location of the contact prongs;

FIGURE 2 is an enlarged side view of the socket assembly of FIGURE 1;

FIGURE 3 is a schematic diagram illustrating a circuit that may be utilized to operate the fiashtube of said application;

FIGURE 4 is an enlarged bottom view of a subassembly of the present invention;

FIGURE 5 is a sectional view, in part, of certain elements of the subassembly of FIGURE 4;

FIGURE 6 is a schematic diagram illustrating a circuit that may be utilized to operate the flashtube of said application at much higher flashing rates;

FIGURE 7 is an enlarged bottom View of a subassembly of a modification of the present invention, that may be used in the circuit of FIGURE 6;

FIGURE 8 is a sectional View, in part, of certain elements of the subassembly of FIGURE 7; and

FIGURE 9 is an enlarged side View of a pulse transformer utilized in the socket assemblies of FIGURES 4 and 7.

It will be easier to understand the present invention by first considering the operation of the circuit illustrated in FIGURE 3. A direct current power supply 12 charges discharge capacitor through impedance 11, which may be a resistor or inductor, as is well known in the art. The voltage on capacitor 10 during charging, and after it is charged, appears across anode 5 and cathode 7 of flashtube 1 by way of conductor and contact prong 15, and conductor 117 and contact prong 17, respectively as illustrated.

. Trigger probes 21, 23, 25, 27 and 29 are each connected through respective contact prongs 121, 123, 125, 127 and 129 to a terminal of each of separate isolating capacitors C Likewise, sparker electrode 48 is connected through contact prong 49 to a terminal of another separate isolating capacitor C Note that the other sparker electrode, 47, is connected within fiashtube 1 to cathode 7.

The other terminals of isolating capacitors C are connected by common line 51 to one terminal of the secondary winding 53 of pulse transformer 52. The other terminal of secondary winding 53 is connected in common with one terminal of primary winding 54 by way of conductor 61 to one output terminal of trigger circuit 55, which may be grounded. The other terminal of primary winding 54 is connected by Way of conductor 62 to the other terminal of trigger circuit 55. Trigger circuit 55 may comprise a thyratron or other switching circuit adapted to charge a capacitor (not shown) and to discharge it through primary winding 54 to produce a trigger pulse in secondary winding 53. Trigger circuit 55 may be controlled by a stroboscope frequency control 57 such as that illustrated in United States Letters Patent No. 2,331,317, issued on October 12, 1943, to Kenneth J. Germeshausen.

Assume that discharge capacitor 10 is fully charged. Its voltage appears across anode 5 and cathode 7, and also on sparker electrode 47. Upon receipt of a signal from stroboscope frequency control 57, trigger circuit 55 operates, delivering a trigger pulse to primary winding 54 of pulse transformer 52. The trigger pulse created in secondary winding 53 is transmitted through isolating capacitors C to trigger probes 21, 23, 25, 27 and 29 and to sparker electrode 48. The voltage potential between sparker electrodes 47 and 48 is suflicient for breakdown to occur resulting in an arc therebetween. As disclosed in said application, this assures that the tube will fire in complete darkness. The main flash breakdown occurs first between cathode 7 and trigger probe 21; thence to trigger probe 23 and so on to anode 5. The function of isolating capacitances C is to assure that these breakdowns occur in series from cathode 7 to anode 5. For example, when breakdown occurs between cathode 7 and trigger electrode 21, the isolating impedance between trigger electrodes 21 and 23 prevents the potential of trigger electrode 23 from immediately dropping to cathode potential. Then breakdown occurs in the same manner between trigger electrodes 21 and 23, and so on to anode 5. Thus, the voltage applied between cathode 7 and anode 5 can become discharged in the space between them, producing a brilliant flash of light.

In summary, my invention comprises a socket assembly into which the contact prongs of fiashtube 1 may be inserted. Capacitance means are provided between contact prong 49, contact prongs 121, 123, 125, 127 and 129, and the secondary winding 53 of pulse transformer 52. The elements enclosed within dotted line 40 of FIGURE 3 are assembled in one small compact unit. Incapsulation is provided to eliminate exposed high voltage radiating points and to ruggedize the assembly.

In one commercial form, called the FX-6A by the manufacturer, Edgerton, Germeshausen & Grier, Inc., the flashtube of said application has such small dimensions that its contact prongs may be arranged for insertion into a miniature nine-pin radio tube socket, as can be seen upon examination of FIGURES 1 and 1A. Thus, when flashtube 1 of FIGURE 1A is turned over for insertion into socket assembly 30, contact prong 17 will fit into contact prong socket 217, contact prong 49 into contact prong socket 249, etc. Note that there is one blank contact prong not connected to anything within flashtube 1. Accordingly, there is one blank contact prong socket which is not connected to anything as will later appear. The blank contact prong is added to aid in strengthening the mechanical connection between flashtube 1 and socket assembly 30. Any suitable mounting means may be provided for mounting socket assembly 30 into equipment. One such means, mounting plate 31, is illustrated in FIG- URES 1 and 2.

FIGURE 4 illustrates the elements of socket assembly 30 before incapsulating and adding mounting plate 31. FIGURE 5 illustrates the method of mounting contact prong sockets 215 and 229. First, a series of nine radial holes, 36 apart, are drilled in circular body 80 of electrically insulating material. Body 80 has a face 81 and a surface 82 on the side thereof opposite face 81. Conducting sleeve 83 may be mounted on body 80 by inserting it through a hole and peening over its edge as illustrated at point '75 in FIGURE 5. Other suitable mounting means that are well known in the art may be used. Note that the contact prong engaging portion of sleeve 83 confronts face 81 of body 80, and that the major portion of sleeve 83 extends outwardly from and normal to surface 82. The inside diameter of sleeve 83 is such that a contact prong 115 will fit snugly therein. Contact prong sockets 215 and 217, and the blank contact prong socket, are mounted in this manner. Insulated conductors 115 and 117 are connected, as illustrated at 76 (FIGURE 5) by soldering, or other wellknown means, to contact prong sockets 215 and 217 respectively.

The construction of the remaining contact prong sockets is exemplified by contact prong socket 229 illustrated in FIGURE 5. Here, conducting sleeve 90 has a dielectric insulating material 91 coated on its inside surface, permanently adhering thereto. Sleeve 90 with its insulating coating 91 may then be inserted in a hole and peened over as illustrated at 77 in FIGURE 5. The inside diameter of dielectric insulating material 91 is such that a contact prong 129 will fit snugly therein. The thickness of dielectric insulating material 91 is selected so that the capacitance between a contact prong 129 and conducting sleeve 90 will be approximately equal to the desired value of C Contact prong sockets 221, 225, 227, 223, and 249 are similarly constructed.

Pulse transformer 52 is mounted at the center of circular body 80 by gluing it to surface 82, or by using some other suitable adhesive, or by using a non-magnetic machine screw 78 and nut 79, as illustrated. Insulated conductors 61 and 62 extend out from pulse transformer 52 as illustrated. Conductor 62 is connected to one terminal of primary winding 54 (not shown in FIGURE 4) of pulse transformer 52. Conductor 61 is connected in common with the other terminal of primary winding 54 and a terminal of secondary winding 53 (also not shown in FIGURE 4). The other terminal of secondary winding 53 is connected by insulated conductor 51 to sleeves 90 of contact prong sockets 221, 225, 229, 227, 223, and 249 as schematically illustrated in FIGURE 4.

When the subassembly of FIGURE 4 is completed, dummy contact prongs (not shown) may be inserted into all contact prong sockets, and the unit incapsulated with electrically insulating material. Dummy contact prongs are used to keep all contact prong sockets clear of incapsulating material. Obviously other means may be used to do this. During this process, care must also be exercised to insure that insulated conductors 61, 62, 115 and 117 are properly located so as to extend through the mass of electrically insulating material to the exterior, as illustrated in FIGURES 1 and 2.

When it is desired that the fiashtube 1 be discharged at high flashing rates the circuit of FIGURE 6 is utilized. Resistors R through R; are connected in the circuit of FIGURE 3 as illustrated in FIGURE 6. Their function is to fix the amplitude of the voltage gradients created between adjacent electrodes within flashtube 1 when the voltage of fully charged capacitor 14) appears across cathode 7 and anode 5. Otherwise spurious breakdown might occur between any pair of adjacent electrodes causing flashtube 1 to flash spuriously.

FIGURE 7 illustrates the subassembly before incapsulating, and adding mounting plate 31, of the socket assembly utilized in the circuit of FIGURE 6.

FIGURE 8 illustrates the construction of the contact prong socket of FIGURE 7. Again, a series of nine radial holes, 36 apart, are drilled in circular body of electrically insulating material. Conducting sleeves 83 are mounted in all such holes by any suitable means. The contact prong engaging portions of sleeves 83 confront face 81 of body 80 and the major portions of such sleeves extend outwardly from and normal to surface 82 of body 86. The inside diameters of sleeves 83 are such that the contact prongs will fit snugly therein.

Next, sleeves of dielectric, insulating material 85 may be shrunk-fit on the sleeves 83 of contact prong sockets 249, 221, 223, 225, 227, and 229 only. Other suitable mounting means may be used. Then metal sleeve 86 is mounted around insulating sleeve 85 by, for example, a press fit, or other suitable means. Alternatively, sleeve 36 with an insulating coating permanently fastened to its inside surface may be mounted on sleeve 83 by suitable means. It will be obvious that care must be exercised to avoid damaging insulating sleeve 85. Moreover, the dimensions of sleeves 83, 85 and 86 are selected so as to have the required capacitance C between sleeves 86, and sleeve 83 and its contact prong.

Pulse transformer 52 may then be mounted and connected as heretofore explained. Then resistors R through R are mounted between sleeves 83 as illustrated in FIGURE 7. In the case of said FX6A, in one application, these may be 0.1 watt, 4.7 megohm resistors. The circuit may be traced from contact prong socket 217 (connects to cathode 7) through resistor R; to contact prong socket 249 (connects to starter 49) through resistor R to contact prong socket 221 (connects to trigger electrode 21) through resistor R to contact prong 223 (connects to trigger electrode 23) through resistor R to contact prong socket 225 (connects to trigger electrode 25) through resistor R to contact prong socket 227 (connects to trigger electrode 27) through resistor R to contact prong socket 229 (connects to trigger electrode 29) through resistor R to contact prong socket 215 (connects to anode 5).

When the subassembly of FIGURE 7 is completed, dummy contact prongs (not shown) may be inserted into all contact prong sockets and the unit incapsulated with electrically insulating material. Again, conductors 61, 62, and 117 must be properly located so as to extend through the mass of electrically insulating material to the exterior as illustrated in FIGURES 1 and 2.

To facilitate understanding the invention, the views of FIGURES 1, 1A, 2, 4, 5, '7, 8 and 9 have been purposely enlarged. Attainment of the objects of the invention will clearly appear upon consideration of a typical example. The dimensions of said FX-6A is A; inch in diameter by 1 inches overall height including the length of the contact prongs which is inch. A socket assembly 30 made according to the embodiments disclosed herein may be one inch in diameter by inch high. The volume of such socket assembly 30 is less than the volume of the envelope of said FX6A. It will clearly appear that a socket assembly of extremely compact size and rugged construction has been provided. Further, it will be noted that fiashtube 1 requires capacitors C and pulse transformer 52, and, in some applications resistors R R R R R R and R and that these circuit elements have been constructed and assembled in a minimum of space.

Moreover such construction has reduced conductor lengths and the number of exposed high voltage radiating points thereby minimizing spurious radiation.

Those skilled in the art will readily devise many modifications to the present invention which are within the intended scope thereof. It is therefore intended that the scope of the present invention be not limited by the foregoing disclosure, but rather only by the appended claims.

The invention claimed is:

1. A socket assembly, for use with a flashtube having a plurality of contact prongs, a pair of which must be connected to the terminals of an electrical circuit and the remainder of which must be capacitively coupled to a common connection, said socket assembly comprising, in combination:

a body of electrically insulating material having a face and a surface on the side thereof opposite the face, and

a plurality of passageways extending therethrough parallel to and spaced about a common axis normal to the face;

a pair of electrically conductvie sleeves permanently mounted one each in each of two of said passageways, and having a prong engaging portion confronting the face and a portion extending outwardly from the surface thereof, for engaging the said pair of contact prongs of said flashtube;

a plurality of further electrically conductive sleeves permanently mounted one each in each passageway of the remaining passageways,

each having a prong engaging portion confronting the face and a portion extending outwardly from the surface thereof, and

having its inner surface coated with dielectric, insulating material, such that, when one of said remaining prongs of said fiashtube is caused to engage said coated sleeve, a capacitance exists between said prong and said sleeve;

a pulse transformer mounted on the surface of said body, and disposed within the outwardly extending portions of said sleeves,

said pulse transformer having a primary winding with two terminals and a secondary winding with two terminals with one terminal of its secondary winding connected internally to one terminal of its primary Winding;

means connecting electrically the other terminal of said secondary winding of said pulse transformer in common with said plurality of further electrically conductvie sleeves;

four insulated conductors connected one to each of the terminals of said primary winding of said pulse transformer and to each of said pair of electrically conductive sleeves for connecting the same to said terminals of said electrical circuit; and

a mass of electrically insulating material extending from the surface of said body and said pulse transformer, and

incapsulating said outwardly extending portions of said electrically conductive sleeves, and said connecting means, with said four insulated conductors extending through said mass of insulating material to the exterior thereof.

2. A socket assembly, for use with a flashtube having a plurality of electrodes and having an exterior contact prong connected to each electrode, a pair of which contact prongs must be connected to the terminals of an electrical circuit and the remainder of which contact prongs must be capacitively coupled to a common connection, said socket assembly comprising, in combination:

a body of electrically insulating material having a face and a surface on the side thereof opposite the face, and

6 a plurality of passageways extending therethrough parallel to and spaced about a common axis normal to the face; a pair of electrically conductive sleeves permanently mounted one each in each of two of said passageways, and having a prong engaging portion confronting the face and a portion extending outwardly from the surface thereof, for engaging the said pair of contact prongs of said flashtube; a plurality of further members permanently mounted one each in each passageway of the remaining passageways, each having a prong engaging portion confronting the face and a portion extending outwardly from the surface thereof, and each said further member comprising a first electrically conductive sleeve having a dielectric, insulating material disposed concentrically about its outer surface and a second electrically conductive sleeve disposed concentrically about said insulating material, such that, when one of said remaining prongs of said flashtube is caused to engage said member, a capacitance exists between said prong and said second electrically conductive sleeve; a pulse transformer mounted on the surface of said body, and disposed within the outwardly extending portions of said pair of electrically conductive sleeves and said further members, said pulse transformer having a primary winding with two terminals and a secondary winding with two terminals, with one terminal of its secondary winding connected internally to one terminal of its primary winding; means connecting electrically the other terminal of said secondary winding of said pulse transformer in common with said second electrically conductive sleeves of said further members; four insulated conductors connected one to each of the terminals of said primary winding of said pulse transformer and to each of said pair of electrically conductive members for connecting the same to said terminals of said electrical circuit; and a mass of electrically insulating material extending from the surface of said body and said pulse transformer, and incapsulating said outwardly extending portions of said pair of electrically conductive sleeves and of said further members, and said connecting means, with said four insulated conductors extending through said mass of insulating material to the exterior thereof. 3. A socket assembly as in claim 2 further comprising resistors disposed among and adjacent said pair of electrically conductive sleeves and said further members, and so connected electrically as, when said fiashtube is caused to engage said socket assembly, to provide a resistance between adjacent electrodes of said flashtube.

References Cited in the file of this patent UNITED STATES PATENTS 2,421,780 Frear June 10, 1947 2,667,573 Satinoff Jan. 26, 1954 2,787,735 Scal Apr. 2, 1957 2,912,625 Benson Nov. 10, 1959 2,916,673 Maslin et al Dec. 8, 1959 2,965,807 Fruengel Dec. 20, 1960 2,975,328 Ludeke et al. Mar. 14, 1961 2,977,508 Germeshausen Mar. 28, 1961 2,984,768 Henry May 16, 1961 

1. A SOCKET ASSEMBLY, FOR USE WITH A FLASHTUBE HAVING A PLURALITY OF CONTACT PRONGS, A PAIR OF WHICH MUST BE CONNECTED TO THE TERMINALS OF AN ELECTRICAL CIRCUIT AND THE REMAINDER OF WHICH MUST BE CAPACITIVELY COUPLED TO A COMMON CONNECTION, SAID SOCKET ASSEMBLY COMPRISING, IN COMBINATION: A BODY OF ELECTRICALLY INSULATING MATERIAL HAVING A FACE AND A SURFACE ON THE SIDE THEREOF OPPOSITE THE FACE, AND A PLURALITY OF PASSAGEWAYS EXTENDING THERETHROUGH PARALLEL TO AND SPACED ABOUT A COMMON AXIS NORMAL TO THE FACE; A PAIR OF ELECTRICALLY CONDUCTIVE SLEEVES PERMANENTLY MOUNTED ONE EACH IN EACH OF TWO OF SAID PASSAGEWAYS, AND HAVING A PRONG ENGAGING PORTION CONFRONTING THE FACE AND A PORTION EXTENDING OUTWARDLY FROM THE SURFACE THEREOF, FOR ENGAGING THE SAID PAIR OF CONTACT PRONGS OF SAID FLASHTUBE; 